Rear Adm. Joseph Tofalo, Director of Undersea Warfare, said he expects to receive answers in May to his question of whether ship builders could build three submarines per year.

"The biggest issue is finding the man power pool in an economy that is also coming back. That is probably the biggest challenge. During the decade of the 80s this country built three SSNs (attack submarines) and one SSBN (ballistic missile submarine) every year for about a decade. This country can do amazing things when challenged," Tofalo said.

In total, the Navy will have 71 submarines in 2016, including 14 nuclear-armed Ohio-class submarines, or SSBNs; four Ohio-class submarines converted to conventionally armed guided-missile boats, or SSGNs; Los Angeles-class fast attack submarines, or SSNs; three Sea Wolf submarines and 11 Virginia-class submarines, also SSNs.

Even though the Navy is currently producing two new Virginia-class attack submarines each year, an anticipated shortfall of submarines is expected to grow worse in coming years as more Los Angeles-class fast-attack submarines retire at a faster pace than Virginia subs are added. Senior Navy leaders have suggested that the service may delay retirement of some Los Angeles-class boats.

"We are going to drop below the minimum requirement of 48 (attack submarines) even with the two per year build rate – so we've got to sustain that two-per year build rate and figure out ways to work through that trough, or a low point. Unfortunately, we will go down to 41 SSNs at one point," Tofalo said.

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The Virginia-class attack submarine inventory will drop to 41 in 2029, according to the Navy's recently released 2016 30-year shipbuilding plan. Ultimately, the plan calls for a fleet of 50 Virginia-class submarines by the mid-2040s.

Rep. Randy Forbes, R-Va., Chairman of the House Armed Services Committee's Seapower and Projection Forces subcommittee, would like to see a larger submarine fleet but does not building the current industrial base could handle building three per year.

"There is no question that I am worried about the overall fleet size. It would be great for us to be able to do that but I think, however, it is a little bit challenging for the industrial base to be able to be able to pull that off. While I think that would be a good goal to have, my suspicion is that is probably not going to happen in the short term and we will stick to doing two per year," Forbes told Military.com in an interview.

Virginia-class submarines are built by a cooperative arrangement between the Navy and Electric Boat, a subsidiary of General Dynamics and Newport News Shipbuilding, a division of Huntington Ingalls Industries.

Each industry partner constructs portions, or "modules," of the submarines which are then melded together to make a complete vessel, industry and Navy officials explained. Thus far, 11 Virginia-class subs have been delivered to the Navy, and seven are currently under construction. Like other programs, the Virginia-class submarines are broken up into procurement blocks.

Blocks I and II, totaling 10 ships, have already been delivered.

The first Block III Virginia-class Submarine, the USS North Dakota, was delivered last year.

On Dec. 22, 2008, the Navy awarded a contract for eight Virginia-class submarines. The third contract for the Virginia-class, or Block III, covering hulls numbered 784 through 791 -- is a $14 billion multi-year procurement, Navy officials said.

Multi-year deals are designed to decrease cost and production time by allowing industry to shore up supplies in advance and stabilize production activities over a number of years. Budget uncertainties connected to sequestration have made these deals more difficult.

The Block III subs, now under construction, are being built with new so-called Virginia Payload Tubes designed to lower costs and increase capability, Navy officials explained.

Instead of building what most existing Virginia-class submarines have -- 12 individual 21-inch in diameter vertical launch tubes able to fire Tomahawk missiles -- the Block III submarines are being built with two-larger 87-inch in diameter tubes able to house six Tomahawk missiles each.

The first several Block IV Virginia-class submarines are under construction as well -- the USS Vermont and the USS Oregon. Last April, the Navy awarded General Dynamics' Electric Boat and Huntington Ingalls Industries Newport News Shipbuilding a $17.6 billion deal to build 10 Block IV subs with the final boat procured in 2023.

Design changes to the ship, including an alteration in the materials used for the submarines' propulsor, which will enable Block IV boats to serve for as long as 96-months between depots visits or scheduled maintenance availabilities, Navy officials said.

The program's current two-boats per year production schedule, for about $4 billion can be traced back to a 2005 challenge issued by then Chief of Naval Operations Adm. Mike Mullen. Mullen challenged the program to reduce production costs by 20 percent, saying that would allow the Navy to build two Virginia-class submarines per year, Navy officials indicated.

This amounted to lowering the per-boat price of the submarines by as much as $400 million each, he added.